Torque Conversion Chart: N·m, ft·lbf, in·lbf, kgf·m

The torque conversion table

Every number in this table is exact by definition: 1 foot = 0.3048 m exactly, 1 pound-force = 4.4482216152605 N exactly, and 1 kgf = 9.80665 N exactly. That makes 1 ft·lbf = 1.3558179483314004 N·m exactly, 1 in·lbf = 0.1129848290276167 N·m exactly, and 1 kgf·m = 9.80665 N·m exactly. The table is rounded to 6 decimal places.

Check the identities: 1 ft·lbf = 12 in·lbf exactly (12 inches in a foot); 1 N·m = 0.737562 ft·lbf, so 100 N·m = 73.7562 ft·lbf; 1 kgf·m = 9.80665 N·m, so 10 kgf·m = 98.0665 N·m. The table reads both ways: the ft·lbf column of the 1 N·m row (0.737562) is the reciprocal of the N·m column of the 1 ft·lbf row (1.355818).

The worked example, line by line

Setup: 100 N·m, converted to ft·lbf, in·lbf and kgf·m.

Line 1 — the exact factors. 1 ft·lbf = 1.3558179483314004 N·m; 1 in·lbf = 0.1129848290276167 N·m; 1 kgf·m = 9.80665 N·m.

Line 2 — foot-pounds. 100 ÷ 1.3558179483314004 = 73.7562 ft·lbf.

Line 3 — inch-pounds. 100 ÷ 0.1129848290276167 = 885.0746 in·lbf.

Line 4 — kilogram-force metres. 100 ÷ 9.80665 = 10.1972 kgf·m.

Reverse: the ft·lbf equal to 100 N·m are 73.7562 (exact 73.7562149); the forward at the displayed value is 100.0000 N·m. The kgf·m equal to 50 ft·lbf are 6.9127 (exact 6.9127477); the forward at the displayed value is 49.9997 ft·lbf. The in·lbf equal to 10 N·m are 88.5075 (exact 88.5074579); the forward at the displayed value is 10.0000 N·m. The N·m equal to 1000 in·lbf are 112.9848 (exact 112.9848290); the forward at the displayed value is 999.9997 in·lbf. The ft·lbf equal to 200 N·m are 147.5124. The kgf·m equal to 25 ft·lbf are 3.4564. Both forwards land a hair under their round targets — 49.9997 ft·lbf against 50, and 999.9997 in·lbf against 1000 — because the displayed values are rounded to four decimals; that is rounding in the fourth decimal place, not error, and the exact values above are the authoritative ones.

Every branch, checked

25 ft·lbf: 33.8954 N·m, 300.0000 in·lbf, 3.4564 kgf·m. Twenty-five foot-pounds is exactly 300 inch-pounds — the 12-times rule with no rounding at all.

500 in·lbf: 56.4924 N·m, 41.6667 ft·lbf, 5.7606 kgf·m. Five hundred inch-pounds is 41 and two-thirds foot-pounds — the repeating decimal 41.6667 is the only rounded figure here.

10 kgf·m: 98.0665 N·m, 72.3301 ft·lbf, 867.9617 in·lbf. Ten kilogram-force metres is just under 100 newton-metres — a handy rule of thumb is that 1 kgf·m is almost 10 N·m.

1 N·m: 0.737562 ft·lbf, 8.850746 in·lbf, 0.101972 kgf·m. The single newton-metre row of the table — the three numbers to remember.

Lug-nut example: 80 ft·lbf is 108.4654 N·m and 100 ft·lbf is 135.5818 N·m. Most car lug nuts are torqued to 80–100 ft·lbf, which is 108–136 N·m on a metric torque wrench.

20 N·m: 14.7512 ft·lbf. Twenty newton-metres — a common small-bolt torque — is just under 15 foot-pounds.

What the defaults assume

The model assumes the exact definitions: 1 foot = 0.3048 m, 1 pound-force = 4.4482216152605 N, 1 kgf = 9.80665 N. Nothing is measured or estimated — every conversion is exact arithmetic from those three definitions, rounded only at display (4 decimal places in the converter, 6 in the table). Zero converts to zero: 0 N·m is 0.0000 ft·lbf. One inch-pound is 0.112985 N·m, 0.083333 ft·lbf and 0.011521 kgf·m. One thousand newton-metres is 737.5621 ft·lbf and 101.9716 kgf·m. Half a foot-pound is 0.677909 N·m. Rounding convention: conversions are computed from unrounded values, so rounded parts may differ in the last digit from their rounded sum; the reverses are nearest-value solutions at 4 decimal places.

Output · formula · meaning

Who uses this

• The home mechanic torquing lug nuts to 80 ft·lbf: they learn it is 108.4654 N·m on their metric wrench — and they check the 100 ft·lbf row (135.5818 N·m) for the top of the range.
• The cyclist setting a 20 N·m stem bolt: they learn it is 14.7512 ft·lbf — and they check the 1 N·m row (0.737562 ft·lbf) for the unit itself.
• The engineer reading a 500 in·lbf spec: they learn it is 56.4924 N·m — and they check the 10 kgf·m branch (98.0665 N·m) for the metric side.
• The student checking the 12-times rule: they learn 25 ft·lbf is exactly 300.0000 in·lbf — and they check the 1 ft·lbf row (12.000000 in·lbf) for the exact identity.

Accuracy & limitations

The math is first-principles and exact: 1 foot = 0.3048 m, 1 pound-force = 4.4482216152605 N, 1 kgf = 9.80665 N — all three are definitions, not measurements, so the conversions have no error at all; only the displayed rounding (4dp in the converter, 6dp in the table) is approximate. What the model cannot do is set YOUR torque: it converts units, it does not tell you what torque a bolt needs — always use the manufacturer’s specification, and a torque wrench, not a conversion chart. For bolt torque specifications, see the bolt torque chart; for wire sizes, see the AWG wire ampacity chart; for number-base conversions, see the binary, hex and decimal chart; for Allen key sizes, see the Allen key size chart; and for air conditioner sizing, see the air conditioner size chart.